This invention relates to wrapping articles in heat-sealed tubular material of thermoplastic film, in which the air is evacuated before the final sealing.
In prior apparatus of this type, a length of film from a supply roll is drawn into a tubular former along with successive articles to be wrapped. There is a slot along the top of the former and the margins of the film are drawn up around the articles to project through this slot in face to face relationship so that they can be heat-sealed together by means of a pair of cooperating heated rolls. In addition, an elongated pipe having at least one inlet opening and connected to a source of vacuum projects into the former along its bottom surface to evacuate air from the film wrapping as it is being sealed.
However, since this pipe lies at the bottom of the former, the articles being wrapped continually come in contact with it, and, in the case of food products, this creates an insanitary condition. In addition, this contact between the articles and the air evacuation pipe can sometimes cause articles to be caught by the pipe and create trouble in the operation of the apparatus.